The present invention relates to the structure of the head portion of a magnetic disk apparatus and, more particularly, to a floating head slider integrated with a magnetic head and a method of manufacturing the floating head slider.
In the head portion of a magnetic disk device, a conventional magnetic head mounting floating head slider having a taper at an air flow leading edge and two rails which are formed on both sides of the slider in the widthwise direction parallel to the longitudinal direction has been basically used. It is known to build floating head sliders with the following characteristic features, high air film rigidity, mechanical workability using simple rail shapes, floating amount design facilitation.
Manufacturing methods for this slider are roughly classified into two types according to the types of read/write elements. In one manufacturing method, a conductive wire is wound onto a ring consisting of ferrite or the like in the shape of a coil, and a magnetic head called a ring type magnetic head having a gap partially formed therein is used. According to this method, after forming rails of a slider, a ring type magnetic head adheres to the air flow trailing edge face of the rail, and finally, the slider is polished to accurately position the magnetic head.
In the other method, a magnetic head called a thin-film magnetic head in which the same arrangement as that of the above magnetic head is formed to have a flat shape is used. Magnetic heads are formed by a thin-film process on a substrate serving as a base material of sliders, the substrate is cut along the rows, and rails are formed in each slider.
The second method is advantageous to decrease the sizes of a magnetic head and a slider and manufacture highly accurate, uniform magnetic heads. In addition, since a magnetic head formed according to the second method can be stacked and formed together with a signal reproducing head (MR head), this manufacturing method is popularly used at present.
Along with the recent development of a more compact magnetic disk apparatus having high-speed access and a high recording density, a slider must realize a small floating amount of 0.1 .mu.m or less while the slider has a small size, a light weight, and a small load. It is important to design a rail shape which has high air film rigidity and forms a pressure distribution for improving disk tracking characteristics.
In recent years, there has been a trend to change head access mechanisms from linear head access to rotary head access mechanisms to improve high-speed access. In this case, an angle (yaw angle) between the longitudinal direction of the slider and the tangential direction of a track on a disk continuously changes during access. For this reason, in a two-rail slider, pressures generated by the rail surfaces change considerably, and the balance between these pressures is lost, thereby causing the roll angle and the pitch angle to vary. Therefore, the floating stability of the slider must be assured in consideration of an air flow speed which increases toward the outer periphery of the disk, setting of the yaw angle, the center of a load acting on the slider.
In addition, at present, in many magnetic disk apparatuses, a start/stop scheme called a CSS (Contact Start Stop) in which the rail surfaces of a slider are brought into sliding contact with a disk is employed. In this case, in order to reduce damage to the magnetic head and the disk surface caused by intermittent sliding contact between the slider and the disk, the shape of the slider must be designed to shorten the time required for interface sliding and to reduce the probability of damage to the magnetic head and the disk surface.
As a means for solving the above problems, conventional sliders having a complex rail surface shape, and a complex recess shape such as those disclosed in Japanese Patent Laid-Open Nos. 2-101688 and 4-356765 have been developed. Since the rail shapes of these sliders are difficult to form by normal machining, these rail shapes are normally formed by wet or dry etching using masks. In this case, since a magnetic head is formed first, the magnetic head must be protected during etching to form the rails and a recess. Some slider material requires a long etching time, and magnetic head protecting performance is degraded, thereby causing a decrease in yield.